Sediment transportation systems to the Levant basin and the role of the Nile River since the Pliocene

The progradation of the Nile River Delta and the thick (~1500m) Sinai-Israel shelf since the Pliocene provide a world class source to sink system feeding a deep (>1.5 km) siliciclastic basin.  The general agreement that the Pliocene-to-Recent succession originates from the Nile Delta dispersing sediments via a system of counterclockwise currents does not reveal how the sediments were transported to the deep basin. Particularly, how sediments originating from the Nile Delta could have bypassed the ~50 km wide Sinai-Israeli shelf. Here, we examine the various sources that contributed to the accumulation of the Pliocene-to-Recent succession in the deep Levant basin, and the temporal and spatial contribution of each source. The analysis of a unique seismic data set covering the shelf, slope and deep basin enable us to track submarine sediment transport systems.

Following attribute analysis of the seismic volumes we map channel sets, analyze their morphological features and interpret their erosional and depositional patterns. Direction flow maps indicate that sediments sources vary from eastward remnant Arabian drainage network at the onset of the Pliocene, to direct Nilotic origin during the Pliocene. Since the Late Pleistocene reworked sediments, deriving from the Israeli shelf and northern Sinai provide a major source to the deep basin. Furthermore, our results demonstrate an increase in channel’s complexity since the Early Pliocene to Recent suggesting a gradual transition from sporadic submarine flow events, carrying fewer sediments to the deep basin at the Early Pliocene, to more frequent events during the Late Pleistocene-to-Recent characterized by an increase in sediment load. The gradual increase of channel complexity from Pliocene-to-Recent is discordant to the general trend of sea-level fluctuation, suggesting that sea-level has a minor effect on sediment accumulation in the deep basin. We propose that the balance between the northward prograding Nile Cone and the longshore currents building the Sinai-Israeli shelf dictate siliciclastic accumulation in the southeastern Mediterranean basin as well as the paleogeography of its margin.